CODEWITHSUNDEEP
pythonxml
pepourquier
pepourquier

Reputation: 16

Python lxml / XPathEvalError : Invalid expression when I parse xml file

I try to parse an XML file with lxml. It works with some files but the last one gave me an error:

XPathEvalError at /admin/xml_exportation/xml/add/
Invalid expression

Here is the xml code :

<?xml version="1.0" encoding="utf-8" ?>
<export source="Source" version="1.0" date="2014-02-21T17:46:57">
  <Agence ID="XX1" externRef="XX1" customCode="38495">
    <Biens>
      <Bien ID="XX1-176" ref="XX1-176">
        <DateMAJ>2013-06-14T12:12:07</DateMAJ>
      </Bien>
    </Biens>
  </Agence>
</export>

And then the python code :

tree = etree.parse(xml_file) 
root_path = '/export/Agence/Biens/Bien/'
for element in tree.xpath(root_path): 
   print(element)

I tried to change the path but it gave me the same error.

Thank you for your help.

EDIT

Internal Server Error: /admin/xml_exportation/xml/add/
Traceback (most recent call last):
  File "/home/python-envs/website.com/local/lib/python2.7/site-packages/django/core/handlers/base.py", line 115, in get_response
    response = callback(request, *callback_args, **callback_kwargs)
  File "/home/python-envs/website.com/local/lib/python2.7/site-packages/django/contrib/admin/options.py", line 372, in wrapper
    return self.admin_site.admin_view(view)(*args, **kwargs)
  File "/home/python-envs/website.com/local/lib/python2.7/site-packages/django/utils/decorators.py", line 91, in _wrapped_view
    response = view_func(request, *args, **kwargs)
  File "/home/python-envs/website.com/local/lib/python2.7/site-packages/django/views/decorators/cache.py", line 89, in _wrapped_view_func
    response = view_func(request, *args, **kwargs)
  File "/home/python-envs/website.com/local/lib/python2.7/site-packages/django/contrib/admin/sites.py", line 202, in inner
    return view(request, *args, **kwargs)
  File "/home/python-envs/website.com/local/lib/python2.7/site-packages/django/utils/decorators.py", line 25, in _wrapper
    return bound_func(*args, **kwargs)
  File "/home/python-envs/website.com/local/lib/python2.7/site-packages/django/utils/decorators.py", line 91, in _wrapped_view
    response = view_func(request, *args, **kwargs)
  File "/home/python-envs/website.com/local/lib/python2.7/site-packages/django/utils/decorators.py", line 21, in bound_func
    return func(self, *args2, **kwargs2)
  File "/home/python-envs/website.com/local/lib/python2.7/site-packages/django/db/transaction.py", line 223, in inner
    return func(*args, **kwargs)
  File "/home/python-envs/website.com/local/lib/python2.7/site-packages/django/contrib/admin/options.py", line 1007, in add_view
    self.save_model(request, new_object, form, False)
  File "/home/python-envs/website.com/local/lib/python2.7/site-packages/django/contrib/admin/options.py", line 740, in save_model
    obj.save()
  File "astucesexperts/apps/xml_exportation/models.py", line 154, in save
    for element in tree.xpath(root_path): # Find each new property
  File "lxml.etree.pyx", line 2115, in lxml.etree._ElementTree.xpath (src/lxml/lxml.etree.c:57669)
  File "xpath.pxi", line 370, in lxml.etree.XPathDocumentEvaluator.__call__ (src/lxml/lxml.etree.c:146579)
  File "xpath.pxi", line 238, in lxml.etree._XPathEvaluatorBase._handle_result (src/lxml/lxml.etree.c:144977)
  File "xpath.pxi", line 224, in lxml.etree._XPathEvaluatorBase._raise_eval_error (src/lxml/lxml.etree.c:144832)
XPathEvalError: Invalid expression

I also add the code from an xml file I could export with the script (changing the root path).

<?xml version='1.0' encoding='UTF-8' ?>
<ANNONCES>
    <ANNONCE>
        <AGENCE_REF><![CDATA[22]]></AGENCE_REF>
        <AGENCE_NOM><![CDATA[Agence]]></AGENCE_NOM>
<REFERENCE><![CDATA[100lm]]></REFERENCE>
        <TRANSACTION><![CDATA[2]]></TRANSACTION>
        <TYPE><![CDATA[2]]></TYPE>
        <SOUSTYPE><![CDATA[45]]></SOUSTYPE>
        <SURFACE><![CDATA[100]]></SURFACE>
    <ANNONCE>
</ANNONCES>

Upvotes: 0

Views: 1490

Answers (2)

Michael Anderson
Michael Anderson

Reputation: 73440

Your XPath has a trailing '/'. Remove it and everything works as expected.

That is, change:

root_path = '/export/Agence/Biens/Bien/'

to 

root_path = '/export/Agence/Biens/Bien'

Upvotes: 1

ArunasR
ArunasR

Reputation: 2005

Your closing tag for <Biens> has no backslash, so your tree is empty because XML did not parse.

Validate your XML before you try parsing it in Python.

Upvotes: 0

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